Oriental rat flea

transmission of

plague

...that rat fleas carried the plague bacillus. The following year Paul-Louis Simond, a French researcher sent by the Pasteur Institute to India, announced the results of experiments demonstrating that Oriental rat fleas (Xenopsylla cheopis) carried the plague bacillus between rats. It was then demonstrated definitively that rat fleas would infest humans and transmit plague through...

typhus

...as its principal reservoir of infection the Norway rat; occasionally, the common house mouse and other species of small rodents have also been found to be infected. The rat flea Xenopsylla cheopis is the principal carrier of the disease, and transmission to humans occurs through the medium of infected flea feces. The frequency of occurrence of human cases is...